The field of art to which this invention pertains is the production of a distillable hydrocarbon stream from a first distillate hydrocarbon stream, a second distillate hydrocarbon stream and a waste lubricant stream. The waste lubricant stream is contacted with a hot hydrogen-rich gaseous stream to increase the temperature of this feed stream and to vaporize at least a portion of the distillable hydrocarbonaceous compounds, thereby producing a distillable hydrocarbonaceous stream which is immediately hydrogenated in an integrated hydrogenation zone. The vaporized waste oil stream is admixed with a first distillate hydrocarbon stream before introduction into the hydrogenation zone. The second distillate hydrocarbon stream is convened in a hydrocracking conversion zone in order to produce lower boiling distillable hydrocarbon products and an aqueous ammonia solution. The aqueous ammonia solution is then admixed with a partially condensed effluent from the hydrogenation zone in order to neutralize at least one acid gas. The resulting admixture is partially condensed to produce a distillable hydrocarbon product stream and a hydrogen-rich gaseous stream which is preferably recycled to contact the waste lubricant feedstock.
There has always been a demand for high quality distillate hydrocarbon and recently there is a steadily increasing demand for technology which is capable of reclaiming and of rerefining waste lubricants. Previous techniques utilized to dispose of waste lubricants which are frequently contaminated with halogenated organic compounds and other heteroatomic compounds have frequently become environmentally unpopular or illegal and, in general, have always been expensive. With the increased environmental emphasis for the treatment and recycle of chlorinated organic compounds and waste lubricants, there is an increased need for the conversion of these products when they become spent and unwanted. For example, large quantities of used motor oil are generated and discarded which oil would provide a large potential supply of feedstock for the present invention while providing an environmentally responsible disposal. Therefore, those skilled in the art have sought to find feasible techniques to convert such feedstocks to produce hydrocarbonaceous product streams which may be safely and usefully employed or recycled. Previous techniques which have been employed include incineration and dumping which, in addition to potential pollution considerations, fail to recover valuable hydrocarbonaceous materials.